Yahoo Japan plans to take a 50.1% stake in
Yusaku Maezawa
’s
Zozo Inc.,
3092 -0.45%
which operates a popular fashion site in Japan, paying about $3.7 billion, the companies said Thursday.

Mr. Maezawa, who will step down as the site’s chief executive, is one of Japan’s most prominent tech entrepreneurs, known for his attention-grabbing exploits. He paid $110.5 million for a Jean-Michel Basquiat painting of a black skull in 2017 and last year appeared with
Tesla Inc.
TSLA -0.27%
’s Mr. Musk to announce that he had bought the first ticket to fly around the moon on a SpaceX vehicle.

Mr. Maezawa has been trying to revitalize Zozo, which reported a decline in annual profit for the year that ended in March. It was the first such drop since the company’s shares went public in 2007. The cost of developing and delivering the body-measuring Zozosuit, which Mr. Maezawa had thought would become a catalyst for growth, weighed on its profits.

Yahoo Japan, which operates a widely used shopping site in Japan, said it would buy Zozo stock at ¥2,620 ($24.30) a share. It said Mr. Maezawa, who currently owns a 36.8% stake in the company, would sell most of those shares—a 30.4% stake—to Yahoo Japan.

Zozo shares rose 15% in early Tokyo trading to ¥2,495, just below Yahoo Japan’s offer price. Yahoo Japan said it would begin a tender offer in early October, but added that Zozo would keep its separate listing, so not all shareholders who wish to sell can necessarily do so.

Yahoo Japan is independent of the Yahoo website in the U.S. The U.S. Yahoo site is owned by
Verizon Communications Inc.
’s media unit, while Yahoo Japan is listed in Tokyo. Its shares were up slightly on Thursday.
SoftBank Group Corp.
and its Japanese telecommunications unit together owned 47.5% of Yahoo Japan shares as of March 31.

Mr. Maezawa founded Zozo in 1998 as a seller of imported CDs and records. The company made it to the top of Japan’s e-commerce fashion world by offering leading brands on its Zozotown site that previously were available only in elite department stores.

But the chief executive has acknowledged that his attempts to develop the Zozosuit—with sensors and an app to take body measurements—and a Zozo house brand of clothing haven’t taken off.

Customers complained that using the suit didn’t result in a particularly good fit and some called it a publicity stunt. As investors grew skeptical about Mr. Maezawa’s vision for Zozosuit, the company’s stock price fell in half.

He has been working on a new project to offer customers better-fitting shoes. The company is preparing to distribute the Zozomat, which combines a smartphone app with a special paper mat that has markers to enable users to take 3-D scans of their feet.

His departure may have come as a surprise to investors, but he was known for making swift decisions.

Referring to a Japanese proverb that says sitting three years on a cold stone will make it warm, Mr. Maezawa told the Journal, “I sit on that stone for three days. I can’t wait for three years.”

WSJ opens select articles to reader conversation to promote thoughtful dialogue. See the 'Join the Conversation' area to the rightbelow for stories open to conversation. For more information, please reference our community guidelines. Email feedback and questions to moderator@wsj.com.